I’m toying with the idea of a car engine + generator for power backup

[Gyro]

I remember when Mobil 1 synthetic first came out. Big advertising campaign - quieter operation, more power, longer life etc. I decided to try it in my old VW Golf.  It proceeded to pi$$ out of every seal and gasket on the previously dry engine! 

[bdunham7]

I remember when Mobil 1 synthetic first came out. Big advertising campaign - quieter operation, longer life etc. I decided to try it in my old VW Golf.  It proceeded to pi$$ out of every seal and gasket on the previously dry engine! 

Yes, that was a Group IV PAO synthetic without an adequate additive package and that was not an uncommon result.  Certain seal polymers could actually become 'crispy' in fairly short order.  Lubrication was an issue as well and if you had the original SOHC VW engine, you may have ground up the camshaft lobes as well.

[Gyro]

Lubrication was an issue as well and if you had the original SOHC VW engine, you may have ground up the camshaft lobes as well

Ha, yes, quite possibly. Luckily the sills rusted out not long after - It had been previously owned by a garage and had been steam cleaned within an inch of its life, removing all the protective coatings!

[AaronD]

I remember when Mobil 1 synthetic first came out. Big advertising campaign - quieter operation, longer life etc. I decided to try it in my old VW Golf.  It proceeded to pi$$ out of every seal and gasket on the previously dry engine! 

Yes, that was a Group IV PAO synthetic without an adequate additive package and that was not an uncommon result.  Certain seal polymers could actually become 'crispy' in fairly short order.  Lubrication was an issue as well and if you had the original SOHC VW engine, you may have ground up the camshaft lobes as well.

That would explain the rumors then.  I guess it's similar to the idea that "vinyl and tube amps are sacred and everything else is ****!"  That opinion was formed when it was a new technology compared to a mature one, and it stuck.  But now that we've figured out how to do the new stuff right, it's far superior.

[brucehoult]

IMO the odds of those three Subaru’s being truly stock is zero!

You can be sure those cars were disassembled blueprinted ( probably tweaked) and reassembled by a specialist with years of experience.

I recently read an article about an endurance test Goodyear did To promote their new tire of the day, I think they raced a Mustang or Shelby around Indy or some similar oval track at high speeds like that for an extended period.

Apparently the entire power train, cooling system etc. was tweaked, better bearings, cooled transmission and differential etc.

Yeah, it's hard to say. I took a look at the FIA's appendix D. There is a list of allowed modifications (many compulsory for speeds over 250 km/h, optional below) to production cars (Category B) including adding a roll cage, racing seat and harness, safety fuel tank. No mention is made of what if anything may or may not be done to things such as the drivetrain between being picked from the production line and used for the record attempt.

You'd think it would defeat the purpose if parts with higher specification were allowed to be fitted. Selecting three vehicles from the production line and then allowing the competitor to decide which one to run seems to be the intended mechanism for dealing with manufacturing variations.

Wikipedia cites a case "Category B Group III had a Dodge Dakota with a top speed of 217.395 mph.[16] Forums citing the Dakota's top speed indicate a standard production Dakota R/T would only reach about 125 mph." If true, that makes an absolute mockery of Category B being "production" vehicles.

In April/May 2005 Mercedes took the 100000 km record from Subaru and also set a new 100000 mile record.

From their press release (https://www.mercedes-benz-media.co.uk/en-gb/releases/233):

"The world-record run took place under the supervision of the FIA, which sets strict rules for tests of this kind. The participating vehicles were selected at random, sealed and shipped to the USA by the FIA officials at DaimlerChrysler’s Sindelfingen plant. Before, during and after the record run, the test vehicles were monitored continuously by the FIA until the world record was recognised officially. In accordance with the globally recognised regulations, the extent of any repairs which may be performed is limited and the replacement of entire assemblies such as the engine, transmission or exhaust system is not allowed."

That sure sounds as if nothing can be touched in Category B. (there is a defined 2000 km run-in period allowed)

[Circlotron]

Wikipedia cites a case "Category B Group III had a Dodge Dakota with a top speed of 217.395 mph.[16] Forums citing the Dakota's top speed indicate a standard production Dakota R/T would only reach about 125 mph." If true, that makes an absolute mockery of Category B being "production" vehicles.

Seeing required tractive effort goes up with the square of the speed, and power with the cube of the speed, that vehicle would need 5.26 times as much power to go at 217 mph vs 125 mph. Doesn't sound like a standard vehicle by a long shot.

[james_s]

That depends on what is limiting the top speed. In some cars it is the gearing, the engine will redline in top gear and that is your top speed. In other cars it is power, many cars have a higher top speed in 4th gear than in 5th due to the increased torque available.

[brucehoult]

Wikipedia cites a case "Category B Group III had a Dodge Dakota with a top speed of 217.395 mph.[16] Forums citing the Dakota's top speed indicate a standard production Dakota R/T would only reach about 125 mph." If true, that makes an absolute mockery of Category B being "production" vehicles.

Seeing required tractive effort goes up with the square of the speed, and power with the cube of the speed, that vehicle would need 5.26 times as much power to go at 217 mph vs 125 mph. Doesn't sound like a standard vehicle by a long shot.

It would be completely ridiculous.

I think someone has confused km/h with mph.

The highest speed for any record in Category B Group III is currently 141.604 mph 227.889 km/h for a 1 mile flying start by a Mazda6 4-Door Skyactiv-D, followed closely by the same vehicle's 1 km flying start, 100 mile standing start, and 1 hour standing start. That and the Mercedes E320CD (1 hour standing start, 50000 miles, 100000 km) are the only vehicles to break 140 mph in Category B Group III (diesel, "supercharged" by which I take it they really mean forced induction of any kind).

So that Dakota, if it had a record at some time (it doesn't now) was almost certainly 135.083 mph 217.395 km/h.

[james_s]

(diesel, "supercharged" by which I take it they really mean forced induction).

That's exactly what supercharged has always meant, forced induction. Turbochargers were originally called turbo-superchargers, and before that crankshaft driven superchargers have been around for a long time.

[John B]

Interesting bit of trivia: try to find the supercharger that was crank driven, but also exhaust powered. I can think of 1 car that it was used in.

[bdunham7]

Interesting bit of trivia: try to find the supercharger that was crank driven, but also exhaust powered. I can think of 1 car that it was used in.

Is that a trick question and you are referring to the Chrysler Turbine Car?  The only (piston) engines I know of with an arrangement like you describe are large radials with power recovery turbines.  Did someone put one in a car?

[james_s]

Interesting bit of trivia: try to find the supercharger that was crank driven, but also exhaust powered. I can think of 1 car that it was used in.

I don't know about a car, but that has been used in large diesel engines like the sort used in locomotives and tugboats and such.

[John B]

No trick question. It was used in a diesel, but nothing exotic. A regular Japanese brand car manufacturer. This supercharger design was probably also used in a few niche applications.

[bdunham7]

I don't know about a car, but that has been used in large diesel engines like the sort used in locomotives and tugboats and such.

If you mean turbo-compounding, I'm not sure that is exactly what he is describing.  There are actually over-the-road trucks that use turbo-compounding as well (Detroit DD15). 

[brucehoult]

IMO the odds of those three Subaru’s being truly stock is zero!

You can be sure those cars were disassembled blueprinted ( probably tweaked) and reassembled by a specialist with years of experience.

Ah-ha! I think I've gotten to the bottom of this.

The 2005 Mercedes effort that holds the current 100,000 km (and also 100,000 mile) outright records were set with a Category B genuine mass production car.

The 1989 Subaru effort that held the outright 100,000 km record until 2005 was in a Category A car -- that is: anything goes. They actually still today hold the Category A record. Preparing the cars for the 1989 run was the start of Subaru's "STi" performance group. According to the article at ...

https://www.jcars.co.nz/blog/2020/4/10/jdm-unicorns-episode-5-subaru-legacy-rs-ra-a-type

"The year is 1988 and Subaru establishes a new performance motor sport wing called Subaru Technica International “STi” to take charge of all of Subaru’s motor sport conquests. STi’s first mission was to prepare a group of new Legacy RS BC’s for Subaru’s purpose of beating a series of land speed records including the big one, the 100,000km land speed record endurance test. With Subaru seeing some success with the Leone in rallying a RS “Rally Sport” variant of the Legacy was to be produced to celebrate this and provide a base as Subaru’s new WRC car. The RS Legacy’s 2L EJ20G closed deck, quad cam, intercooled, turbo boxer engine produced an impressive 220PS for its day. STi took this base and enhanced it further fitting forged pistons and strengthened connecting rods along with porting and polishing the inlet and exhaust ports on the heads. The Crankshaft, Flywheel and even the clutch cover was hand balanced by STi. A second radiator fan was also added for enhanced cooling which was a fair call considering the test would take place at the Arizona Test Center. The suspension was upgraded along with the steering ratio quickened. In January 1989 STi with a team of 24 drivers and 3 cars hit the track for the 100,000km endurance sprint. STi pushed the cars to the limit running them flat out around the massive 5.7 mile banked speedway non stop over 18 and a half days smashing the previous record along with 13 others at the same time with an average speed of 223.34km/ph. Cars only took a pit stop every two hours to change drivers whilst refueling, changing oil or tires. The record stood for 15 years until it was beaten. But more impressively Subaru encountered rain which is rare in Arizona but still succeeded. Prior to that the cars had been averaging 233.35km/ph. 10km/h might not sound much but Mercedes Benz who broke the record and still hold it today achieved a 225.9km/h average speed meaning had it not rained Subaru’s old faithful BC Legacy RS could still hold the record some 31 years later."

STi's involvement is also mentioned in wikipedia: https://en.wikipedia.org/wiki/Subaru_Tecnica_International#Endurance_record

[james_s]

I don't know about a car, but that has been used in large diesel engines like the sort used in locomotives and tugboats and such.

If you mean turbo-compounding, I'm not sure that is exactly what he is describing.  There are actually over-the-road trucks that use turbo-compounding as well (Detroit DD15).

The turbo-compounding I'm familiar with is the Wright R-3350 which in some configurations had three power recovery turbines that recovered energy from the exhaust flow and used viscous couplings to transfer it to the crankshaft. I don't remember where I read about the mechanically assisted turbocharger but I found mention of it in a wikipedia article, apparently it was used by some EMD 2 stroke medium speed diesel engines. A 2 stroke diesel requires forced induction since it has a conventional lubricated crankcase and cannot use the underside of the piston to push air into the cylinder to drive the exhaust out.

"In the case of Electro-Motive Diesel's two-stroke engines, the mechanically assisted turbocharger is not specifically a twincharger, as the engine uses the mechanical assistance to charge air only at lower engine speeds and startup. Once above notch # 5, the engine uses true turbocharging. This differs from a turbocharger that uses the compressor section of the turbo-compressor only during starting and, as two-stroke engines cannot naturally aspirate, and, according to SAE definitions, a two-stroke engine with a mechanically assisted compressor during idle and low throttle is considered naturally aspirated."

[John B]

OK, it was the pressure wave supercharger:

https://en.wikipedia.org/wiki/Pressure_wave_supercharger

The crankshaft connection provides a quasi-timing role, but essentially the intake air is compressed by directly being forced by exhaust gas.



Here's a video of it in action on a Mazda capella 626. Note that this video is from only January 2020, although I've known about these things since 2004? when I was more into the mazda 6 platform, finding videos of this one is like finding hens teeth, let alone seeing a running example in person.

[David Hess]

It's a huge issue.  There are, or at least were, industrial engines designed for this purpose with huge roller bearings and extra-stout crankshaft stubs, but absent those design features a radial load is not good for long term operation and may even snap a crankshaft quite quickly unless you used a coupling shaft driving a pulley with its own very robust bearings.  Most designs using belts for power transfer are crude, low-volume machines that just weren't worth the effort to engineer a proper powertrain.  There are exceptions as belts do protect from extreme shock loading for things like concrete saws and stump grinders.  Even there, though, belts are less common these days.

Belt driven generator setups are not unknown, but to connect them directly with belts you do need a generator assembly that is designed for the purpose, just like the engine.  I've never seen a chain drive and suspect that it would be challenging to make that quiet and reliable.

The reason I like the idea of using a belt and pulleys is that I think it would be easier than finding a 4-pole generator.  A 1:2 or whatever transmission would work just as well but I know I can get belts, pulleys, and whatever is required to use them.

That would explain the rumors then.  I guess it's similar to the idea that "vinyl and tube amps are sacred and everything else is ****!"  That opinion was formed when it was a new technology compared to a mature one, and it stuck.  But now that we've figured out how to do the new stuff right, it's far superior.

There are definite differences in performance, like with dampening, but comparisons are usually made with flawed solid state designs that suffered in clipping.  Frequency compensation is not bandwidth control!

The cobbler's children go shoeless, right?  The amplifier that I use has a pair of Texas Instruments class-D TPA3116D2 chips.  If I ever get back into audio amplifier design, maybe I will build something for myself.

100 hours is a lot of power outages. I've put 33 hours on my generator in the ~3 years I've owned it. I change the oil once a year regardless of the hours. Unless you're living off grid and using the generator full time this is not going to be an issue. If you are, it might be worth considering an external oil tank as is used with dry sump engines.

I have ended up using my backup generator for between 6 to 12 hours per year.

[SeanB]

If going belt driven you will first need to add a flexible coupling to the generator input shaft, then have a pair of bearings in pillow blocks mounted to drive it, and then the pulley for the belt or chain drive. Reason is because most alternator drive shaft input bearings are not rated for large radial loading, they merely are there to align the rotor with the stator, and the bearings do not have the load ability to handle your belt tension plus the torque the belt or chain will create on them.

You will need the coupling to isolate the radial torque, and the pillow blocks, with appropriately sized shaft, generally a few sizes bigger than the input shaft for stiffness, and the pillow blocks to handle this very large load. Your pillow blocks will handle the radial load perfectly fine with the larger bearings they have, and in general you sort out most of your alignment there, leaving the flexible coupling to take up the rest, plus any vibration from the belt or chain. All standard parts available off the shelf from mechanical parts suppliers, including the ready made stub shafts with keyways already cut.

Same for the car engine output, the bearings there are also not rated for radial load, and need the same treatment. the crankshaft axial load rating is there only for the thrust from the clutch or torque converter, and radial loading capacity is there only to keep the crankshaft centred, as the set of main bearings in parallel absorb the thrust of the pistons only, they have an oil film that will only handle that.

[bdunham7]

OK, it was the pressure wave supercharger:

https://en.wikipedia.org/wiki/Pressure_wave_supercharger

The crankshaft connection provides a quasi-timing role, but essentially the intake air is compressed by directly being forced by exhaust gas.

I thought I'd seen it all.  I guess not! 

[NiHaoMike]

How come nobody mentioned the idea of just using the engine and generator as they are in the car, with the car still usable as a car for normal times?
http://priups.com/riddle/answer-1.htm

[David Hess]

How come nobody mentioned the idea of just using the engine and generator as they are in the car, with the car still usable as a car for normal times?
http://priups.com/riddle/answer-1.htm

Some hybrid vehicles can be used that way, but a 12 volt alternator is only large enough to provide a minimum of backup power.  I guess you could make a Rube Goldberg setup with multiple car alternators feeding a big inverter.

[BradC]

How come nobody mentioned the idea of just using the engine and generator as they are in the car, with the car still usable as a car for normal times?

Because it's only < $1000 if you already own a Prius?

[brucehoult]

How come nobody mentioned the idea of just using the engine and generator as they are in the car, with the car still usable as a car for normal times?

Because it's only < $1000 if you already own a Prius?

I just checked trademe.co.nz and it's now possible to pick up a 2004 or so Prius for NZ$3500 (US$2400), so it's not crazy.

The quoted power levels are surprisingly low though -- there are normal cars with alternators that can put out 2500 or 3000 W. Hell, my 1995 BMW motorcycle does 800 W so you can run electrically-heated clothing for rider and passenger.

[Berni]

The idea of using a hybrid car is pretty good, however you will most likely have to build your own inverter.

In order to still use the car as is, you would have to tap off the high voltage battery pack and make sure you do it in a way that does not upset the cars electronics. That thing is about 150 to 350V of rather intimidating DC. So you really need to know what you are doing, while you can't easily buy an off the shelf inverter for the correct input voltage. Best bet might be buying an giant old UPS and modifying it.

Taking just the engine of a hybrid car does already solve the mechanical problem of mounting a generator onto the internal combustion engine. The motor/generator on it will be 3 phase but most likely will not produce 50/60Hz at the correct voltage. So you still likely need big power electronics to turn it into DC and then convert that up to mains AC.

Doing it from the 12V system is not even worth a try because the alternator can't produce that much. You might get about 300W to 1000W out of there.